Agreed on the included bag. I think that will be more than enough for most use, especially since it's designed to carry the unit, controller, charger, and three batteries (using the external pouches). Everything in a little compact case that you can throw in a suitcase or carryon.

I'm sorry but that DJI shoulder bag (euro man purse) is a terrible design. Call it a satchel if you want but Indiana Jones would not use that either. Just get your favorite backpack and throw it in there use the rest of the space for water and snacks, then go have fun flying.

The mavic folded up reminds me of the old days when we used handheld camcorders with the flip-screen and baby sized VCR tapes. Maybe those padded camcorder bags could make comeback.
For now, Girlfriend has room in her handbag. I will pocket the controller and tell the missus it's a 4 blade foldaway heatless hair dryer that oddly takes selfies.

Considering the size of the Mavic, any small DSLR camera bag should do. They also come padded and with extra pockets, great for spare battery, some memory cards, etc. At Amazon these bags are dime a dozen, so no need to buy anything fancy. Just check dimensions to make sure you have enough internal space to store everything.

I already own a Slingshot Edge 150 for my camera gear. Its a great bag. And it looks like with a little bit of rearranging that I should still be able to carry my camera gear around with me, AND fit a Mavic in the top pouch.